How to Build an Oil Fired Kiln

One of the limitations of creating pottery, either throwing it on a wheel or hand building, is kiln access for firing the pieces. Studio time can be expensive and in some areas, access to kilns is limited or non-existent. Fortunately, innovation and necessity has dictated that kilns can be built relatively easily and cheaply. A small through-draft kiln, 1 to 4 feet wide for example, can be built in an afternoon by an experienced mason.

Things You'll Need

• Hard or soft firebricks
• Cement
• Trowel
• Bow saw
• Oil-fired burner

Instructions

1. Determine where to build and what size to make the kiln, with the size depending on how often the kiln will be used and what type of pottery will be fired. A through-draft kiln consists of three parts: the base which contains the firebox; the kiln chamber, where the pottery sits and the chimney. Inner pathways connect the three parts allowing airflow and heat to move through the kiln and smoke to exit through the chimney.

2. Determine what type of firebrick to use. Kilns constructed from hard firebrick will use more fuel because the brick has poor insulating qualities. Soft firebrick is not as strong, but has higher insulating properties. The bricks can be cut with a bow saw during construction.

3. Lay out the brick to build the base of the kiln. Cementing the bricks together. Build the firebox on top of the base, leaving a space at the opposite end of the burner opening for the heat and flame to move up into the kiln chamber. The firebox should 9 to 12inches in depth. The length determines how large the kiln will be.

4. Build the walls to create a kiln chamber above the firebox. Leave a small opening in the wall to allow access into the kiln chamber. This opening will be bricked up when the kiln is in use. The door bricks should fit tightly and be numbered so they can be put back in the correct place for each firing. The kiln floor will extend two-thirds of the length of the chamber. Build a bag wall on the open end of the floor allowing the flames and heat from the firebox below to move into the kiln chamber, over the pottery and out the chimney on the opposite end. A bag wall is an interior wall the keeps flame and heat from coming in direct contact with your pottery.

5. Build the chimney opposite of the bag wall, adding room for a damper, which regulates air flow into the chimney, up the stack.

6. Add the burner to the firebox through the back opening, locating the oil tank away from kiln where it cannot be knocked over.

References

• "Discovering Pottery;" Harry Memmott; 1972
• "The Self-Reliant Potter;" Andrew Holden; 1984